Monday, May 28, 2018

BNSF/Santa Fe Bridge over I-235 in Oklahoma City, OK

ODOT, one of 12 photos below
It is so nice to see some truss spans being built instead of being blown up. As part of widening I-235, two long spans were needed because the railroad crosses the road on a sharp angle. These trusses are 45' tall. This bridge move reminds me of the move of a 63' high truss in South Chicago.

Oklahoma railroad map: overview and key     detail views

3D Satellite, the bridge being replaced
(new window)

ODTO posted an album of 12 photos with the comment:
The I-235 Off-Broadway project in Oklahoma City takes a dramatic turn starting at 7 p.m. Friday, Jan. 26, as all lanes of the highway are scheduled to be closed for an extended weekend from south of I-44 to N. 36th St. to allow for a spectacular feat of engineering to take place. The interstate is scheduled to reopen no later than 6 a.m. Tuesday, Jan. 30, but potentially could open earlier. Drivers will need to use I-35, I-40, I-44, SH-74/Lake Hefner Parkway and Lincoln Blvd. during this closure. Due to their size and weight, it will be a slow and steady operation to move the two bridge spans into place taking up to a full day per span. The bridge structures will be hoisted up on self-propelled mobile transporters and inched along the highway into their new position over the interstate. This is the first time this innovative bridge-moving technique is being used in Oklahoma, allowing the Oklahoma Department of Transportation to schedule short closures of the highway during the more than two-year interstate widening and reconstruction project.
According to the comments on the video, the project was done before rush hour on Monday.

Hydraulic lifts were used to raise one of the 2-million-pound steel bridge structures nearly 16 feet off the ground to be placed on top of self-propelled mobile transporters







The first bridge was put in place over I-235 Saturday, Jan. 27.



Workers prepare the second I-235 railroad bridge structure to be moved into place later this morning

(new window)  A nice overview of the move (and a couple of trains). The truss is designed to be supported at the ends, but they are supporting it in the middle for the move. Since it is just dead weight, no live weight (i.e. train), it is overbuilt enough that it can tolerate being lifted in the middle. I say it is overbuilt because the size of the member trusses does not vary depending upon their position in the truss. Standardization of the truss members costs more steel, but it simplifies construction. That is, reducing the cost of construction probably offsets the cost of extra steel.

(new window)  I noticed around 1:40 that they didn't start building the mats on the site until the bridge was close. It seems to me that they could have started building the mats as soon as the interstate had been closed and had them built before the bridge arrived. At 1:46 the bridge has arrived, but it has to wait, and wait, for the mats to be finished. At least we get to watch a train go by while the bridge is waiting. Obviously, ODOT doesn't care much about how long they disrupt traffic in the city. I'm sure the workers like the project taking longer because they are getting paid overtime. It makes you wonder how many other projects ODOT does that has such poor planning. Judging by the ruts left in the dirt by the left mover at 2:25, it was a good thing that the soil wasn't much softer.

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